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DESCRIPTION OF MAIN CIRCUIT OPERATION
MODEL RAS-10JH1, RAS-14JH1
1. Reset Circuit
Voltage supply to
pin 2 of IC521
Voltage at pin 7
of microcomputer
The reset circuit initializes the microcomputer program when power is ON or OFF.
Low voltage at pin 7 resets the microcomputer and Hi activates the microcomputer.
When power "ON" 5V voltage rises and reaches 4.4V, pin 1 of IC521 is set to "Hi". At this time the microcomputer
starts operation.
When power "OFF" voltage drops and reaches 4.2V, pin 1 of IC521 is set to "Low". This will RESET the
microcomputer.
5V
2
R552
1
5
3
IC521
0V
Fig. 1-1
Voltage
5.0V
Reset release at 4.4V
Voltage
5.0V
Fig. 1-2
NORMAL : HI
RESET
7
Microcomputer
Power "OFF"
Power "ON"
Reset enter at 4.2V
- 38 -
: LO
RES
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